Electric switch



Sept. 12, 1950 CALDWELL ET AL 2,521,826

ELECTRIC SWITCH 2 Sheets-Sheet 1 Filed July 10. 1947 INVENTORS L w M M DE L l .N RE -m o 5 6 m m A Sept. 12, 1950 J. R. CALDWELL ET AL 2,521,826

ELECTRIC SWITCH Filed July 10, 1947 2 Sheets-Sheet 2 INVENTORS JOHN RCALowELL :87 GEORGENLEMMON fi tmAGENT Patented Sept. 12, 1950 ELECTRIC SWITCH John R. Caldwell, Hampton, Ga., and George N.

Lemmon, Homewood, Ala., assignors to Southern States Equipment Corporation, a corporation of Georgia Application July 10, 1947, Serial No. 760,168

Claims.

This invention relates to electric switches of the type in which a switch arm is moved into closed position with a minimum of friction and then heavy contact pressure is developed between the switch arm and the stationary contact members. One purpose is to provide a switch arm structure in which the conducting members of the switch arm move as a unit to apply or to release the heavy contact pressures. Another purpose is to develop the desired heavy contact pressures without imposing equally heavy strains upon the supporting insulator units. Another purpose is to accomplish the desired results by a smooth, even movement of the control member for the switch, and without the use of books, latches, catches, or similar complications. Other objects will be apparent from the specification and claims.

Referring to the drawings, Fig. 1 shows the operating members of the switch arm in closed position, and also indicates by dotted lines the open position of the switch arm; Fig. 2 is in smaller scale a side view of a single pole switch embodying this invention; Fig. 3 is in larger scale a top view of the operating members of the switch arm when it is in closed position; Fig. 4 explains the motions of some of the operating members; and Fig. 5 is a section on line 5--5 in Fig. 3 showing the slide member which spaces the two sides of the switch arm conductor.

The base I carries two stationary insulators, 2, 3 and one rotative insulator unit ll, which is operable by means of crank 5. The. line or bus connections 6, I are bolted respectively to hinge jaws 26 and switch jaws I3. Insulator 2 carrie a slotted guide 8, and a forked support 9 to which switch jaws Ill, Ill are secured by bolts II--II. Bolts I2, I2 compression springs I3I3 and spacers I4, I4 hold jaws I0, II] in fixed spaced relation but they can be slightly spread by pressures heavy enough to further compress. springs I3, I3.

On insulator 3 is carried hinge support I5 to which the switch arm structure I6 is hinged by pivots ll, [1. Said switch arm includes the supporting arm I8 with its forked end I8Ill, the elongated U-shaped main conductor I9, I9 and the smaller parts connected thereto. The swing end of supporting arm I8 is machined and it fits movably into an opening 26 in main conductor I9. A slide 2I fits movably over the supporting arm I8 as shown in Fig. 5 and it is secured by bolts 22, 22' to the two sides of conductor I9. Supported by opening 23 and slide 2I, main conductor I9 is capable of sliding, reciprocating motion upon supporting arm I8. When in closed position, the tooth I8 of arm I8 fits into the slot in 8, thereby holding insulators 2 and 3 in their proper positions without undue strains.

Rotative insulator 4 is free to turn in bearing 23 which is held by bolts 2424 to hinge law members 25, 25 and 2 B, 26. Jaw members and 26, 26 are secured by bolts 2l-2'I to support I5 and they are formed as shown in Fig. 3 to engage the ends Of main conductor I3, I9. Bolts 28'28, springs 2929 and spacers 303B hold each pair of jaw members 25, 26 in minimum spaced relation to one another but capable of being separated by heavy pressure. As shown in Fig. 1, jaw 25, where it makes contact with conductor I3, has an end that is an arc about the pivot I! as its center. The ends of I3 and 25 are made on corresponding arcs, and all these ends are formed as shown. Each end of main lCOH" ductor I9 is bent first outwardly and then inwardly, the ends of 25, 25, 25, 25 are each bent towards the adjacent end of main conductor I9, but 25 is shorter than 26, and so when the conductor I9 is moved to the left, as shown in Fig. 3, there is no heavy pressure between main conductor I3 and any of the other conducting members. But when conductor I9 is moved to the right, it wedges between the two pairs of hinge jaws 25, 26 and 25, 25, and at the other end conductor I9 wedges between switch jaws I0, I0. As shown in Figs. 1, 2, and 3, the line or bus connections 6 and I, the hinge jaws 26, 2B and 2'l, 2'1, the main conductor IQ of the switch arm structure and the jaws Ill, I 0, all are in the same horizontal plane above base I. Also these members form two substantially straight lines of conductors which join together the two line connections 6 and I. Thus the main conductor I9 is in effect and in appearance a removable portion of a continuous conductor of which 3 and I are parts Pivoted to support I5 b a second pivot 3| is the curved rocker 32 whose swing end is connected by connecting rod 33 to crank 34,which in turn is secured to insulator unit i. Connecting rod, 33 includes a universal joint at each end. Rocker 32 carries a third pivot 35 about which moves link 36. The other end of link 35 is connected by a fourth pivot 31 to supporting arm I8. Links 38, 38 are connected by a fifth pivot, which is bolt 22, to slide 2 I, and they are also connected to link 36 by a sixth pivot 39 at a location between pivots 35 and 31.

It will be seen from Fig. 4 that pivot 35 moves always in an are about its fixed center at 3I. Link 36 is pivoted at 35 and also at 31, and when pivot 35 is moved through the space between lines A and B, the arcs about 3| and 31, respectively, coincide so closely that clearances about the various pivots permit pivot 35 to be moved in this space without link 36 causing pivot 3'! to be moved.

Operation is as follows:

Assuming the switch to be fully closed, the members are as shown in Fig. 1, and pivot 35 will be in the position shown at A in Fig. 4. Also the switch arm main conductor I9 will be wedged tightly between the switch jaws Ill, Ill, and the springs I3, I3 will be further compressed. Each of the other ends of IE) will be wedged between one of the pairs of hinge jaws, thereby slightly spreading 25 from 2 6 and compressing springs 38,

3 slightly. Thus heavy pressure contacts are made both at the hinge ends and at the swing end of the switch arm main conductor 19.

To open the switch, crank 5 is rotated, thereby moving crank 34, connecting rod 33, and moving rocker 32 counter-clockwise from line A- towards line B. Link 36 is thereby movedcounterclockwise and so links 38, 3 8 -are moved to the left and conductor [9 is thereb moved to the left. This releases the heavy pressures atall jaw members, and the parts are shown in Fig. 3 with main conductor i9 free to be raised from its horizontal position.

Further motion of crank 5 brings rocker 32 past line :B, .and since link 36 :keeps pivot 31 a fixed distance from pivot 35, this causes pivot 31 to be raised, thereby raising supporting arm 18 about its fixed pivots ll, .H and so carrying the whole switch arm structure [5 upwards. The ultimate fully open position is indicated by dotted lines in Fig.1.

When closing the switch, the reverse motions occur. By the time pivot ha reached line B, the.:SWitCh arm 18 is in horizontal position and tooth H3. is resting securely in its slot in guide 8. Further clockwise motion of rocker 32 does not move pivot 31, but it does rotate link 35 in clockwisemotion. The leverageapplied through links 38, 38 to conductor I9 is favorable, and so very heavy pressure is developed as 19 is forced between 25, iiiv and 25, 26, at the hinge end, and simultaneously between it, It at the switch jaw end. The tooth l8" and the pivots ll, i'i hold the members a and 5 in a fixed spacing and therefore the heavy pressure developed by i9 does not affect the insulators.

The structures as shown are one design of switch embodying this invention. Many changes or modifications could be made by one familiar with the art without departing from the purpose and spiritof the invention.

Weclaim:

1. In an electric switch a stationary jaw support and a jaw fixedl mounted thereon, a stationary hinge support and a supporting arm mounted thereon by a hinge pivot and engageable with the jaw :support to maintain unchanged the spacing between the hinge support and the jaw support when the switch is in closed position, the said supporting arm supporting a mainconductcr movable axially of said supporting arm, a second fixed pivot also supported by the hinge support 4 being cooperable to develop high pressure ehgagements between the freefends of theU-shaped member and the adjacent jaw members when the main conductor is moved longitudinally in one direction and being cooperable to release the said high pressure engagements when the U-shaped member is moved in the opposite direction.

3. In an electric switch, two spaced insulated supports, a jaw mounted on one of said supports and with its ends extending towards the other supportfa supporting arm hingedly mounted on the other said support, a U-shaped conductor mounted upon the supporting arm and movable longitudinally thereon, the closed end of the U- shaped-conductor being engageable with the ends of said jaws when the switch is in closed position, together with operating means to force the said closed end of the U-shaped conductor between the ends of said jaw.

4. In an electric switch, a hinge support and a switch arm structure mounted thereon, a jaw support including arigid engagement member, a

pair of jaws mounted on the jaw support; the said switch arm structure including a supporting arm directly mounted on a stationary pivot in the hinge support and with a second engagement member near its swing end cooperable with the first said engagement member to maintain unchanged the spacing between the said jaw support and the said hinge support when the switch is in closed position, and a single integral main conductor slidably supported upon said supporting arm and movable axially of the supporting arm, together with means operable in one continuous movement to swing the switch arm structure into closed switch positionand thereupon to slide the main conductor axiallyupon the supporting arm into high pressure contact with the said jaws.

5. In an electric switch suitable for mounting between two spaced ends of aligned 'busconnectors, an insulated jaw support and mounted thereon a pair of jaws which are connected to t and are in alignment with the bus connectors at a space from the hinge pivot, a rocker mounted a ported by the saidlink in spaced relation to both the said third and fourth pivots, and a connection member from the said fifth pivot to the said main conductor, together with means to move the rocker. and thereby to move the said .main conductor axially of the supporting arm to increase or decrease its contact engagement with said jaw.

2. In an electric switch, two spaced insulated supports, a jaw mounted on one of saidsupports, a supporting arm hingedly mounted on the other said support and a hinge jaw also mounted thereon, a U-shaped main conductor mounted on said supporting arm and movable longitudinally into and out of high pressure engagements with both of said jaws, the free ends of said U-shaped conductor being deformed, the adjacent jaw members all being deformed and all said deformations that are adjacent to the jaw support; an insulated hinge support spaced from the jaw support, and mounted on the hinge support a pair of hinge laws that are connected to and are in alignment with the bus connectors that are adjacent to the hinge support; and mounted on the hinge support upon a stationary hinge pivot a switch arm structure that includes a supporting arm with a single main conductor movably mounted thereon, thesaid supporting arm being engageable with the jaw support to maintain fixed spacing between the jaw support andthe hinge support when the switch arm structure is in closed switch location; together with means operable in one continuous motion to swing the switch arm structure into closed switch location and thereupon to. move the main conductor axiailyupon the supporting arm and into high pressure contact with bothpairs of jaws.

J OHN R. CALDWELL. GEORGE N. LEMMON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date arr-e237 Crabbs- Sept. 26, 1939 2,276,257 Caldwell Mar. 19,1942 2,334,313 Caldwell et al Nov. 16, 1.943 

